Chapter 11 - Correlation Diagrams

Abstract

This chapter describes correlation diagrams for pericyclic reactions. The orbital correlation diagram is based on the conservation of orbital symmetry while the state correlation diagram is based on the state symmetries which are determined from orbital symmetries. The construction of the orbital correlation diagram is described in a practical ‘how-to-do-it’ manner following a sequence of four steps. The orbital correlations predict whether a pericyclic process is symmetry-allowed or symmetry-forbidden thermally or photochemically. The orbital correlation diagrams for electrocyclic reactions in neutral and charged systems are presented and discussed. The state correlation diagrams are also included. For cycloaddition reactions, the orbital correlation diagrams for the Diels–Alder reaction, cheletropic cycloadditions, [2+2] cycloadditions, photocycloadditions of benzene and [2+2+2] cycloadditions relating to cycloreversion of cyclohexane and prismane–benzene conversion are described. The state correlation diagram for the [2+2] cycloaddition is included. The orbital correlation diagrams for the Cope rearrangement and group transfer reaction taking the all-carbon model are provided.